Setup the Tsunami Digital Sound Decoder

In the previous post I described the sound upgrade of the Virginian 737. Now I will tune the decoder so the loco will run as smooth as possible.

Remember, this is just a guide, you can (and should) always adjust the settings the way you like the most. It’s just an example of how it could be done.

CV settings Virginian 737

First I set the primary decoder address to 37

CV 1: 37,loc address

Then I set the start voltage to 0 volt

(I’ll explain later how you can get your loco to run very slow, see ‘run slow’ below)

CV 2: 0, start voltage

Next we put some momentum in the decoder, a locomotive this size takes some time to run or stop.

CV 3: 64, accelleration rate

CV 4: 64, breaking rate

And enable the custom speed table.

CV 25: 16, custom speed table

But before the custom speed table will work we had to set the appropriate bit in cv 29.

CV 29: 18, speed table enable

Since I use a Roco Multimaus as my DCC system I need to press a shift key to access F-keys 11 – 20. Therefore I swapped the F7 and F11 key which is done by cv 41 & 45.

CV 41: 128, F7 key is break

CV 45: 8, F11 is dimmer

In order to breake the train when I push F7 we had to put in the brake rate in cv 61.

CV 61: 129, breake rate for F7 key is 32

Next we have to tell the decoder it’s dealing with an articulated engine, that means eight chuff’s with every wheel rotation. I also give it some slip rate, so the chuff’s are out of sync so now and then.

CV 112: 97, dual air pump, medium slip rate, articulated

With cv 115 we assign the whistle for the locomotive

CV 115: 6, whistle

Since I don’t use a cam I have to sync the chuff’s with the wheel rotation by putting some value in cv 116.

CV 116: 180, chuff rate

To match the speaker size with the build-in equalizer set cv 153.

CV 153: 2, equalizer

To make the locomotive automatically make a steam blowdown after a stop, set cv 198.

CV 198: 16, auto steam blow down

The next cv’s you have to set to get your locomotive run very slow. Look at the ‘run slow’ explanation further on.

CV 209: 3, Kp Coefficient

CV 210: 10, Ki Coefficient

If you use the custom speed table, you can set it as I did, but of course you can also put your own value’s in cv 67 towards cv 94.

Custom Speed table:

CV 67: 1

CV 68: 3

CV 69: 5

CV 70: 7

.

. (steps of 3 per cv)

.

CV 91: 49

CV 92: 51

CV 93: 53

CV 94: 55

All others cv’s are default.

Run (very) slow

The Tsunami has a great BEMF control system, but, like all finely tuned items, it needs to be compatible with your loco. Here’s how you get them happy together.